# Copyright (c) 2011 OpenStack, LLC.
# All Rights Reserved.
#
#    Licensed under the Apache License, Version 2.0 (the "License"); you may
#    not use this file except in compliance with the License. You may obtain
#    a copy of the License at
#
#         http://www.apache.org/licenses/LICENSE-2.0
#
#    Unless required by applicable law or agreed to in writing, software
#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
#    License for the specific language governing permissions and limitations
#    under the License.

"""
Scheduler host weights
"""


from nova.openstack.common import cfg
from nova.openstack.common import log as logging
from nova.scheduler.weights import least_cost
from nova import weights

LOG = logging.getLogger(__name__)
CONF = cfg.CONF


class WeighedHost(weights.WeighedObject):
    def to_dict(self):
        x = dict(weight=self.weight)
        x['host'] = self.obj.host
        return x

    def __repr__(self):
        return "WeighedHost [host: %s, weight: %s]" % (
                self.obj.host, self.weight)


class BaseHostWeigher(weights.BaseWeigher):
    """Base class for host weights."""
    pass


class HostWeightHandler(weights.BaseWeightHandler):
    object_class = WeighedHost

    def __init__(self):
        super(HostWeightHandler, self).__init__(BaseHostWeigher)


def all_weighers():
    """Return a list of weight plugin classes found in this directory."""

    if (CONF.least_cost_functions is not None or
            CONF.compute_fill_first_cost_fn_weight is not None):
        LOG.deprecated(_('least_cost has been deprecated in favor of '
                'the RAM Weigher.'))
        return least_cost.get_least_cost_weighers()
    return HostWeightHandler().get_all_classes()
